mockito无效

Most of the times Mockito when() method is good enough to mock an object’s behavior. But when we have to mock a void method, we can’t use when().

大多数时候，Mockito when()方法足以模拟对象的行为。 但是，当我们必须模拟void方法时，就不能使用when() 。

Mockito模拟无效方法 (Mockito Mock Void Method)

Mockito provides following methods that can be used to mock void methods.

Mockito提供了以下可用于模拟void方法的方法。

1. doAnswer(): We can use this to perform some operations when a mocked object method is called that is returning void.doAnswer() ：当调用返回空值的doAnswer()对象方法时，我们可以使用它执行一些操作。
2. doThrow(): We can use doThrow() when we want to stub a void method that throws exception.doThrow() ：当我们想存根引发异常的void方法时，可以使用doThrow（）。

Let’s create a simple class with a void method that we will mock in our test classes.

让我们创建一个带有void方法的简单类，该类将在测试类中进行模拟。

package com.journaldev;public class Employee {private String name;public String getName() {return name;}public void setName(String name) {if (name == null)throw new IllegalArgumentException("Employee Name can't be null");this.name = name;}}

Mockito模拟无效方法示例 (Mockito mock void method example)

Mockito doAnswer() method takes Answer as argument. It’s a functional interface so we can use lambda expression for its implementation.

Mockito doAnswer（）方法将Answer作为参数。 这是一个功能接口，因此我们可以使用lambda表达式实现其功能。

doAnswer((i) -> {System.out.println("Employee setName Argument = " + i.getArgument(0));assertTrue("Pankaj".equals(i.getArgument(0)));return null;
}).when(emp).setName(anyString());

Notice that return null statement is required since we are mocking void method.

注意，因为我们在模拟void方法，所以需要return null语句。

Mockito模拟无效方法与异常 (Mockito mock void method with exception)

Below code snippet shows how to use doThrow() method to mock void methods with the exception.

下面的代码片段显示了如何使用doThrow（）方法来模拟带有异常的void方法。

doThrow(IllegalArgumentException.class).when(emp).setName(null);

JUnit Mockito模拟void方法示例 (JUnit Mockito mock void method example)

Here is a complete example in JUnit where I am using Mockito to mock void method.

这是我使用Mockito模拟void方法的JUnit中的完整示例。

package com.journaldev.mockito.voidmethod;import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;import org.junit.jupiter.api.Test;import com.journaldev.Employee;class JUnitMockitoVoidMethod {@Testvoid test_mockito_void() {Employee emp = mock(Employee.class);doThrow(IllegalArgumentException.class).when(emp).setName(null);doAnswer((i) -> {System.out.println("Employee setName Argument = " + i.getArgument(0));assertTrue("Pankaj".equals(i.getArgument(0)));return null;}).when(emp).setName(anyString());when(emp.getName()).thenReturn("Pankaj");assertThrows(IllegalArgumentException.class, () -> emp.setName(null));emp.setName("Pankaj");assertEquals("Pankaj", emp.getName());}}

TestNG Mockito无效方法示例 (TestNG Mockito void method example)

Since JUnit 5 and TestNG annotations are so similar, we don’t have to any code specific changes in above class to switch from JUnit 5 to TestNG.

由于JUnit 5和TestNG批注是如此相似，因此我们不必在上述类中进行任何代码特定的更改即可从JUnit 5切换到TestNG。

Just remove the JUnit 5 import statements and add below imports to change testing framework from JUnit to TestNG.

只需删除JUnit 5导入语句并添加以下导入，即可将测试框架从JUnit更改为TestNG。

import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertThrows;
import static org.testng.Assert.assertTrue;import org.testng.annotations.Test;

翻译自: https://www.journaldev.com/21834/mockito-mock-void-method

mockito无效